Chassis, generic

C058A Brake Booster Motor A Position Sensor Circuit Range/Performance

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C058A covers a position signal of booster motor A that is electrically valid but not believable. GM uses it widely: its 2016 and 2019 hybrid tables flag a rotor angle changing faster than 73° per ms, the 2019 IBC unit an invalid Hall pattern (all three high or all low) and a frozen signal, the XT4 module a vector length outside 0.6889–1.2996, and the 2023/2025 tables angle jumps beyond 711.2 rad/s – each Type A with MIL. NXP likewise treats Hall patterns 000 and 111 as an interface fault. GM's PIC6614 lists C058A for the Cadillac Lyriq with a brake assist failure message; Stellantis names it alongside C0582 for the Jeep Wagoneer and asks for BSCM and eBooster to be replaced together.

Likely causes

Position sensor delivering implausible angles (Hall element or sine/cosine sensor degraded)
Intermittent contact or interference on the sensor lines causing angle jumps
Booster unit internal fault or position data no longer matching the stored calibration

Symptoms

  • Brake assist failure message, abnormal pedal feel
  • Check engine and brake warning lamps (GM)
  • Fault may be hard to read out with a normal scan tool

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–3,500
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

booster motor a pos sensor

Related codes

C0587C0588C0589C058EC0582

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, nxp.com.